Fuel system



Nov. 16, 1943.

'D. SAMIRAN FUEL SYSTEM v Filed Dec. 15', 1940 5 Sheets-Sheet l Nov. 16, 1943. D SAMIRAN 2,334,220

FUEL SYSTEM Filed Dec. 15, 194C HIL. @L gg- 1 @9 5 l.. f f .Q6 i 39' o.

' Nov. 1,6, 1943. UD. SAMIRAN 2,334,220

"FUEL SYSTEM Filed Dec. 13, 1940 s sheets-sheet s Patented Nov. 16, 1943 Y FUEL sYs'rnM Davia seguiran, Fairfield, ohio Y Application December 13, 1940, serial No. 370,027 Y 22 Claims. (ci. 15a-e6) (Granted under the act of March 3, 1883, as

. amended April 30, 1928; 370 0. G. 757) Still a further object isl to Aprovide a warning The invention described herein may be manu- Y factured and used by or for the'Government for governmental purposes, withoutthe payment to me of any vroyalty thereon.

My present invention relates to a fuel system of the type wherein a high pressure carburetor is supplied with fuel through a selector valve from a plurality ofV fuel tanks.

One object of the invention is to provide a system wherein the failure of fu l from one of the selected tanks will not cause fal ering of the supply of fuel to the carburetor, a reserve supply of fuel being provided between the fuel pump and the carburetor for this purpose, and automatic mechanism being provided todisplace the fuel from the reserve chamber with a pressure sumcient to properly operate the carburetor during the change-over period from an empty'tank to one containing fuel. i

Another object is to provide a system of the general character above mentioned wherein an air eliminator (for eliminating air and vapor from the fuel supplied to the carburetorhsuch as the type Shown in my copending application Serial No. 335,646, filed May 16, 1940, and having a reserve fuel chamber may be utilized to displace the reserve fuel therefrom during the change-over period by providing an air pressure control valve in connection with the air eliminating vent of the air eliminator.

Another object is to provide a fuel system wherein air pumped by the fuel pump after the fuel from one 4tank fails may be utilized as the means to displace the reserve` supply of fuel with sufficient pressure to operate the carburetor, although at a pressure somewhat lower than normal, with an immediate return of the pressure to normal when fuel is subsequently received by the fuel pump from another fuel tank.

Still another object is to provide a system for supplying fuel continuously to a high pressure carburetor during momentary fuel failure from the primary supply source, which provides supplemental fluid pressure for the displacing operation of the fuel from the reserve chamber when air is pumped to the reserve chamber by the fuel pump.

A further object is to provide 'a vmodification of the system wherein a reserve fuel chamber receives fuel initially from the fuel pump before such fuel passes to theY carburetor, and such chamber is arranged for displacement of the fuel therefrom at carburetor operating pressure whenf ever the fuel pressure drops as a result of failure of fuel to the fuel pump.

` vsteps in the operation thereof;

signal which becomes operative at a fuel pressure belownormal, but such pressure being slightly above that which obtains in the fuel reserve chamber whenV air instead of fuel is pumped thereto, such warning signal thereby immediately indicating any increase in fuel pressure as'caused by a subsequent supply of fuel to the fuel pump and before the pressure in the fuel delivery line reaches normal.

Furtherrobjects and advantages vof my present invention willv become apparent after a perusal of the following description when taken in connection with the accompanying drawings, it being clearly understood that said drawings are by way of illustration and example only and are not to be taken as in any way limiting the spirit or scope of the invention. It is further understood that the spirit and scope of my present invention is to be limited only by the prior art and by the terms of the claims appended hereto.

With reference to the drawings, wherein similar characters designate similar parts throughout the several views: l

Figure 1 is a diagrammatic view of a fuel system embodying my invention;

Figure 1a is a diagrammatic view of an air pressure control valve of my system showing a Vslight modification with respectto Figure 1;

Figure 2 is a vertical sectional view through an air pressure control valve which is an important unit of the system; g

Figure 3 is a sectional view on the line 3-3 of Figure 2;v

Figures 4, 5 and 6 are diagrammatic views of a reserve fuel chamber' and the air pressure control valve of my fuel system showing different Figure 7 is a diagrammatic view of a modified system in which I provide an electrically operated air pressure control valve;

Figure 7a is a fragmentary view of another modification, and

Figure 8 is another diagrammatic View showing a further modification, particularly with respect to the reserve fuel chamber.

On the accompanying drawings, the fuel system Y V shown in Figure 1 includes a high pressure carburetor C Vto which fuel is normally supplied by a fuel pump P. The fuel pump P is adapted to receive fuel from a selector valve SV, which valveiis connected with a plurality of fuel tanks indicated with the tanks I, 2 and 3. The valve BV maybe manually operated or may be automatically operated, as disclosed in my copending application Serial No. 348,969, filed July 81, 1940. The selector valve includes an outlet conduit 1 leading through a strainer S to the intake of the pump P by means of conduits tand 3. Abranch conduit I3 also leads tothe intake of a hand pump H adapted to be operatedlmanually incase of fuel failure. 'I'he fuel pump is suitably driven as from the engine of an airplane or other structure in which the fuel system is used.

Outlet conduits I2 and I3 lead from the pumps P and H through a conduit I4 to an air eliminator AE. The air eliminator AE includes an outer bowl I3 and an inner bowl I3, with the conduit I4 communicating with the space between the bowls. Accordingly fuel entering through the conduit I4 must rise around the -bowl I3 and overiiow its upper. edgebefore entering the bowl I3 which serves the purpose of holdings reserve supply of fuel.

An-outlet pipe I1 leads from the bottom of the bowl I3 to an intake housing I3 of the carburetor C. The carburetor C includes a :let or nonle structure having a nozzle tip I3 and a needle valve 23 normally seated in the nozzle to prevent fuel flow into the fuel mixture passageway 2| of the carburetor leading to the intake manifold of theengine. The needle valve 23 is spring seated with the spring set-.so that fuel pressureon a diaphragm 22 will open the. jet whenever the fuel pressure exceeds/a predetermined pressure. Present type high pressure carburetors begin to operate ataboutsix pounds pressure. The chamber 2t' is communicatively connected with the intake manifold at the input side of the carburetor through a conduit 22' to maintain the spring pressure on the diaphragm constant with rela-l tion to the intake -manifold pressure.

The carburetor Cv also includes a vent 3|' controlled` by a oat 3l" and furtherincludes a supercharger SC'having a casing 23 provided with an` intake 24 and a rotor 23 suitably drivenk from the airplane engine. v'I he supercharger BC delivers air at substantially constant sea level pressure to a chamber c Vai: the input side of the carburetor, the supercharged air passing around and through a venturi 23 to the fuel mixture passageway 2l. The pressure through the venturi 23 is communicated by a passageway 21 to a control diaphragm 23 operable through a stem 23 to control a valve 33 within the housing I3. The valve 33 in turn meters the ilow of fuel to the jet I3. Y

'Ihe air eliminator Allv includes a vent passageway 3i leading through a vent conduit 32-to the space inl one ofthe fuel tanks, such as I, above with vent tubes-.33 leading to atmosphere.

For normally controlling the now of eliminated air through the conduits 3| and 32, the air eliminator AE has a oat operated vent'valve 34. the lfloat of which is indicated at 33. 'I'he float 33 is responsive to the level of fuel in the inner bowl I3 of the air eliminator.

Interposed between the conduits 3l and 32, I provide an air pressure control valve AV which will now be. described in detail. The valve AV comprises a valve body having therein a first valve seat 33 and a second valve seat 31. The

valve seat 33 is formed in a stationary sleeve 33, while the valve seat 31 is formed in a floating sleeve 33. The sleeve 33 is adapted to seat against provided for the vhead 34 after adjustment has the fuel therein. The tanks are also provided the seat 33 under the bias of a spring 43. A valve stem 4I extends through the sleeve 33 and has an enlarged part 42 adapted to be seated against the seat 31.

Connected with the portion 42 of the valve stem 4I is an actuating diaphragm 43. The space below the diaphragm 43 is sealed by a sealing dlaphragm 44 and thespace above the diaphragm 43 is sealed by a sealing diaphragm 45. The space between the diaphragms 43 and 43 is subjected to fuel pressure introduced into an inlet 43 of the body of the valve AV from a conduit 41 leading to the fuel delivery line I1 from the air eliminator AE to the carburetor C. 'I'he fuel pressure from the conduit 41 tends to force the diaphragm 43 downwardly` against the action of a spring 43a. A pressure gauge 41a may be located in the line 41 if desired. Fuel pressure at the normal operating pressure for the carburetor C (for instance about fifteen pounds) acts upon the top of the diaphragm 43 with sufficient force to keep the valve sleeve 33 of! the seat 33 to thereby permit free ilow of air from a chamber 43 within the valve AV to a second chamber '43 therein. The chamber 43, as shown in Figure 3, communicates with an inlet 33, while the chamber 43 communicates with an outlet 3|. The inlet 53 is connected to the conduit 3I, while the outlet II is connected to the conduit 32.

The lower end of the valve stem 4I under normal fuel pressure seats against a valve seat 32 formed in a sleeve y33. The sleeve 33 extends through and is gasketed relative to a head 34 on the lower end of thebody of the valve AV. A lock nut 33 normally retains the sleeve 33 against rotation.

A nut 33 is threaded on the inner end of the "sleeve 33 and serves as a follower for the spring 43, the spring being interposed between this follower and the head of the sleeve 33. The nut 33 is provided with a pair of lugs 31 slidable in slots I3 to prevent rotation of the nut but permit axial movement thereof relative to the sleeve 33 when the sleeve is rotated for the purpose of adjusting the tension of the spring 43. Such rotation is possible after the lock nut 33 is loosened and a screwdriver may then be associated with a slot 33 in the lower end of the sleeve for effecting such adjustment. A closure nut 33 is been made.

The valve stem 4| centran the introduction of' pressure into the chamber 43 from an inlet 3I of the valve AV, which inlet is connected by a conduit 32 to the high pressure side of the supercharger SC. A check valve 32a is preferably located in the conduit 32, opening toward the inlet 3|. A passageway 33 is provided in the body of the valve AV for communicating pressure in the inlet 3| to the interior of the sleeve 53. A second passageway 34 leads from the inlet r3| to the space between the diaphragms 43 and 44 to compensate the operation oi' the air pressure control valve AV when the airplane engine is supercharged. In the event that it is not supercharged, then the space between the diaphragme 43 and 44 would be open to atmosphere and the passageway 33 would be closed to prevent escape of air pressure `irom the chamber 43.

The air pressure control valve AV further includes a. signal switch having circuit'controlling contacts 33 and 33. The contact 63 is carried by a bimetal element 31 anchored to a bracket 33. The contact 33 is carried by the upper end of the valve stem 4I. The point of contact making and breaking with respect to the position of the valve stem 4| may be adjusted by means of anadjusting screw 69. 'Ihis screw 68 is' effective to bend the bracket B8 upwardly to a greater or less degree as desired, depending on the position of the contact 66 in relation to the position of the valve member 39 during operation of the system, as will be hereinafter described.

The contacts 85 and 66 are vconnected ywith wires 1li and 1|. The Wire 10 extends from a control switch 12, to which current is supplied by a wire 13 from a battery 14 or any suitable source of current supply. One side of thebattery is grounded as at 15. The Wire 1| connects with one side of a warning signal light 16, the other side of which is grounded at 11.

In Figure la, I show a slight modification wherein the Vvalve sleeve 53 is supplied with supplementary fluid pressure, such as air under pressure from a pump 18 of the vacuum system of the airplane. The check valve 62a is connected by a conduit 19 -with the pressure connection 80 of the pump 18 instead of to the supercharger SC.-

The pressure connection 88 is normally utilized for operating the wing de-icers, and the pump 18 is usually of the vacuum type with its vacuum connection at 8| connected with the various navigating instruments for operating them. The pump 18 is usually engine-driven.

In Figure '1, I show a modified system wherein a solenoid operated air pressure Vcontrol valve AV' and a fuel pressure reSPOnsive switch PS takethe place of the valve AV in Figure 1. Some of the parts in Figure '7 are similar to those in Figure 1 and accordingly bear the same reference numerals.. The parts which are different, or in addition to Figure 1, will now be described speciilcally.

A solenoid casing 82 is mounted on thebody-of the valve AV' and encloses a solenoid coil 88. An armature or plunger 84 is adapted when the coil 83 is'energized to force the stem 88 against the seat 36 and the valve l2 -away from its seat 81, against the tension of the spring III.

For energizing the solenoid coil 88, the belllows 43' of the fuel pressure responsive switch PS is expanded by the spring 48a which brings the slldably movable contact 8'8 into engagement with the stationary contact 85 carried by the compensating bimetal 81.

The switch PS is supplied with current for operating the solenoid coil 88 through wires 85 and 86 and a ground connection at 81.

Since the switch PS is provided for the purpose of operating the valve AV and it is desirable to have a signal lamp operate at a slightly higher pressure, a second fuel pressure responsive switch PS is provided, having make and break contacts 85 and 68. set for closure at a slightly higher pressure than the switch PS. The pressure switch PS' is set so that make and break of the contacts therein takes place within the range of change in pressure with change in the nature of the fluid-(air or fuel) supplied by the tain the pressure in the line between the pump and the carburetor previously established by 'the rate of volume supply of fuel. Likewise, when the pump again begins to pump fuel, there will be an increase in the rate of supply of fluid volume, with a consequent small increase in pressure which, according to practical demonstration, is about one-half of one pound. It is desired to take advantage of this small change in pressure f which the pressure control valve A takes the place of the valve AV in Figure 1 with the air ventlli'l provided in the carburetor C as inFigure 'I'he air pressure control valve A is predeterminately adjusted to limit the pressure in the air vapor eliminator to a value at which it is desired to feed the fuel from the air eliminator to the carburetor. If the pressure in the air eliminator which is communicatively connected to the air chamber a of the pressure control valve exceeds the desired value-say about twelve pounds-then the bellows b and valve c carried thereby'will leave the seat d of the air pressure control valve housing e t'o permit the escape of air through outlet l and tube connection 82, to tank When the air pressure is below twelve pounds and at such value that fuel no longer is contained within the air vapor eliminator and the line connecting the air vapor eliminator to the carburetor, then the air will escape through the air vent 8|' in the carburetor. This condition will vtake place either when the supply of fuel from the primary source fails or when the supply of fuel is first supplied from the source to -the carburetor. l

In Figure 8, I show another modification wherein instead of using the air eliminator AE as a reserve fuel chamber I provide a reserve chamber RS having lower .and upper compart- `ments separated by a diaphragm 88. Most of the parts in this gure are similar to those already described and accordingly bear the same reference numerals. Additional parts begin with reference numeral 88, which indicates a fitting on pump to the air eliminator. That is to say, il?` the top of the reserve supply chamber RS into which the conduit I4 from the pump P extends and from which the fuel delivery line |1 extends to the carburetor C. 'I'he conduit I4 initially 'discharges fuel into the upper compartment of the chamber RS, from a cavity in the fitting 88, and after such compartment is nearly full then the fuel enters an outlet pipe 8| and flows through the conduit I1. 'Ihe entering fuel drives the diaphragm 88 to its lowermost position shown by solid lines, the air under the diaphragm being displaced through the pipe 3| and an air pressure control valve AV', of the kind shown in Figure 7, to the tank by way of the conduit 82. The conduit 82 may lead to atmosphere, but I preferably connect it with one of the fuel tanks so that in the event of breakage of the diaphragm 88 the fuel will be returned to the tank instead of being wasted.

The valve AV' has its inlet 8| connected by the conduit 82 to a suitable source of iiuid pressure, such as the pump 18. so that when needed fluid pressure may be introduced through the conduit 3| to the lower compartment ofthe reserve supply chamber RS for displacing fuel from the chamber. Such displacement results in upward movement of the diaphragm 88 as to the dottedl position illustrated, the fuel being transmitted to the carburetor through the openings 9| and the air or vapor being transmitted through the opening 9|".

Practical operation Referring rst to Figures 1, 4, 5 and 6, Figure 1 shows the position of the parts during normal operation. The air eliminatorrAE is substantially lled with fuel, due to the air having been eliminated from the fuel. During the air eliminating period the iloat valve 34 will be opened whenever there is insufficient fuel in the air eliminator to render the float 35 buoyant. At such time there is of course the presence of air above the fuel in the eliminator, and such air passes outwardlyvthrough the conduit 3| and the valve AV to the conduit 32 and then into the fuel tank I. The valve AV is open atits first seat 36, as shown in Figures 1 and 2, to permit free elimination of the air. The fuel is being delivered at fifteen pounds pressure to the carburetor C and accordingly the jet |9-20 is open, as it requires but six pounds pressure to eifect opening thereof. The pressure of the fuel is maintained at the desired gure by means of a by-pass or relief valve 93 in the pump P. The valve 93 operates against the bias of a spring 94 which may be set for the desired'pressure. The selector valve SV -If the warning signal 1l remains lighted longer Y than two seconds after the pilot has repositioned the selector valve, he knows that the new fuel tank does not contain fuel but the supply of fuel at a pressure suiilcient to operate the carburetor does not falter because air is still being pumped by the pump P into the air eliminator to displace the fuel therefrom at the twelve and one-half pounds pressure. The air for fuel displacement may be supplemented by additional air from the supercharger SC through theA conduit 62 and the check valve 62a whenever such air pressure is in excess of the pressure within the air eliminator and the lower endof the valve stem 4| is off'the seat 52 as a result of a drop in the fuel pressure from normal, as illustrated in Figure 4. The fuel level, for instance, might be displaced to the level and then built up again after the pilot repositions the selector valve SV from the fuel tank 2, for instance, to the fuel tank 3. If the fuel tank 3 contains fuel, then pressure will be immediately built up to extinguish the warning signal 16 and thereafter position the parts of the valve AV as shown in Figure 2, so that normal elimination of air from the air eliminator AE under control of the oat and the float valve 34 will occur.

If the fuel tank 3 does not contain fuel, then the level of the fuel may recede as to the line L3 in Figure 5. In such event, some air is forced to the carburetor and the pressure quickly drops as,

, for instance, to two pounds. Such pressure is inis set for `the fuel pump P to receive fuel from the tank as evidenced by the position of the control handle or indicating blade 92 thereof.

When the fuel supply in the tank is depleted, the fuel pump P will start pumping air from the tank i. high a pressure when pumping air as it does when pumping fuel, and in actual experience I have found that there is a pressure drop of about two and one-half pounds. This drop is indicated on lthe pressure gauge 41a in Figure 4 and it will be noted that the air entering the air eliminator AE has displaced the fuel in -the eliminator'to the level indicated at L1.

When the diaphragm 43 reached a pressure slightly above twelve and one-half pounds (for instance, thirteen pounds), the contact 66 engaged the contact 65 so as to light the warning signal 16. In this way, the pilot is apprised o f the fact that fuel from the tank he has been using has failed and he can thereupon turn the selector valve SV to another tank. If said other tank contains fuel, such fuel will be immediately supplied to the fuel pump P and by it to the air eliminator AE, resulting in the fuel pressure rising in a short time (the duration depending upon the amount of fuel remaining in the chamber of the air eliminator at the time when the change from one tank to another takes place) toits normal pressure (fifteen pounds). As the fuel pressure rises above twelve and one-half pounds, the valve 39 is unseated from the seat 36 to again permit normal air elimination from the air eliminator, and at approximately thirteen pounds pressure the contact I66 disengages the contact '65 to indicate to the pilot that he is receiving fuel from the new source selected by the position of the selector valve. Thus, Within about two seoonds after the selector valve has been repositioned, the pilot knows that the new fuel tank contains fuel and he can thereafter forget about the selector valve until such time as the warning signal 16 flashes on again.

The pump P is unable to maintain as suilicient for opening the needle valve 20 of the carburetor jet and accordingly there is no further advantage in supplying fuel to the carburetor, since it cannot be forced from the jet and atomized. It is then desirable to quickly eliminate air from the air eliminator AE and the valve AV is accordingly constructed so that the excessively low pressure of two pounds wil1 permit the spring 43a to overcome the spring 4U, due to the low pressure on top of the diaphragm 43, and thereby open the valve AV at the second seat 31. 'I'he chamber 48 is now in communication with the chamber 49 along the enlarged bore in the head of the sleeve 39 surrounding the stem 4|, so that the air in the air eliminator and that air which is subsequently pumped into it may readily escape through the conduits 3| and 32. If the engine has faltered and stopped, the hand pump H can be operated for pumping fuel from the next fuel tank to which the selector valve SV isturned, so that the engine can be started and the air eliminator n again filled with fuel from the fuel pump P.

Finally, when -fuel is supplied to the air eliminator, the level of the fuel may rise, as to the line L4 in Figure 6, by the time the pressure gauge gets up to thirteen pounds. The signal switch 65-66 will be opened at thirteen pounds immediately after the sleeve valve 39 leaves the seat 36 for permitting air elimination under control of the float valve 34 in the normal manner. In the operation of the fuel system shown in Figure 7, substantially the same operating steps take place as described in connection with Figures 1, 4, 5 and 6; The onlydiiference is that the valves 39 and 42, instead of being directly operated from the fuel pressure responsive diaphragm 43 of Figure 2, are operated by energization of the solenoid coil 83 under control of the pressure switch PS. The warning signal 16 of Figure 7 is then controlled by the pressure switch PS', the two switches being set for operationat twelve and one-half and thirteen pounds, respectively. The results obtained are the same in either case. 'I'he pressure control valve AV of Figure 'ldoes not have any equivalent for the second valve and seat 42--81 of Figure 2 tapermit air elimination when the fuel pressure goes down to two pounds, so that the float valve of the air eliminator AE must take care of eliminating the excess air.

In the operation of the modification of my system shown in Figure 8, it is obvious that a failure of fuel will operate the pressure switch PS the same as in Figure 'l for operating'the solenoid controlled air pressure control valve AV and thereby permitting the introduction of fluid pressure from the line B2 through the conduit 3| -to the lower compartment of the reserve supply chamber RS below ther diaphragm 88 therein. This will effect movement ofthe diaphragm as to the dotted position illustrated for displacing the reserve fuel from the chamber RS. Suchl an arrangement is particularly desirable in conn nection with a pump P' of the type -which is inf efcient in pumping air after the fuel supply fails. Where the type .of fuel pump that can pump air is used, then fluid pressure from-the line 62 supplements such air and suitable provision would have to be made for eliminating the air, such as an eliminator built into the carburetor or located between the reserve supply chamber RS and the carburetor.

My system takes advantage of the possibility of the fuel pump pumping air into the air eliminator for the purpose of displacing fuel to the carburetor at a pressure sufficient to operate the carburetor. It also takes advantage of the few pounds drop in pressure in the fuel system as a result of the fuel failing and the pump thereby pumping air, and utilizes such drop as a; means to first operate a warning signal Vand then condition the air eliminator so that its normal air eliminating operation is discontinued so that the.

fuel pump can keep up the desired pressure for displacing the reserve fuel from the air eliminator. One advantageous result of such a system is that the pilot is immediately notified of fuel failure so that he can operate hisselector valve and, within the space of about two seconds, know whether or not there is fuel in the new tank to 4which the selector valve has been set. If the indicator light goes out, he knows that further fuel is being received by the fuel pump, whereas if it stays on longer than two seconds he knows that it is necessary to turn the selector valve to another position. Thus, valuable time is saved between the failure of fuel from one tank and the pick-up of fuel from another tank that contains fuel. Faltering of the engine is also delayed While the reserve supply of fuel has been carburetor, an air eliminator in said fuel delivery line including a float operated air eliminating event of fuel failing from said one of said tanks,

said means comprising an air pressure control means for said vent and having a pressure responsive actuating element responsive` to the pressure of fuel from said air eliminator, which, upon predetermined drop in pressure in said fuel delivery line of said carburetor as caused by said fuel pump receivin-g air operatesrsaid'means forA rendering said vent inoperative, and, upon subsequent rise of fuel pressure resulting from repositioning said selector valve to communicate with another tankrcontaining fuel, operates said means to again render thevent operative.

`2. A fuel system for a high pressure carburetor comprising a plurality of fuel tanks, a fuel pump, a selector valve between said tanks and said pump and connecting one of the tanks with the pump, a fuel delivery line from the discharge side of said pump to a normally closed and fuel pressure opened jet of the carburetor, an air eliminator in said fuel delivery line including a float operated air eliminating vent, means for closing said vent in the event `of fuel failing at the intake of said fuel pump, said means comprising an air pressure control valve in the vent having an actuating element responsive to-the pressure of fuel from said air eliminator, which, upon predetermined drop in pressure thereof below normal and above the pressure required to open said carburetor jet as caused by said`fuel pump re ceiving air moves said actuating element and said element closes said valve, and subsequent rise of fuel pressure resulting from change of said selector valve to another tank containing fuel again moves said actuating element and said element opens said valve, and a signal device responsive to fuel pressure of a degree intermediate normal pressure and the pressure of the fuel resulting from said fuel pump pumping air.

3. In a fuel system for a high pressure car buretor, a fuel pump, a fuel line from the discharge side of said pump to a normally closed and fuel pressure opened jet of the carburetor,

` an air eliminator in said fuel line, said air eliminatorincluding a float operated air eliminating vent and means for rendering said vent inoperative in the event of fuel failing at the intake side of said fuel pump, said means having an actuating used, so that the selector valve may be turned Y through aseries of several tanks before the enout sacrificing any of the advantages thereof.`

I claim as my invention:

1. In a fuel system for a high pressure carburetor, a plurality of fuel tanks, a fuel pump. a selector valve between said tanks and said pump for providing communication between one of said tanks and said pump, a fuel delivery line from the discharge sideof said fuel pump to a normally closed and fuel pressure opened jet of the element responsive to the pressure `of fuel from said airY eliminator and connected with said vent for rendering it operative and inoperative Whereby predetermined drop in pressure in said fuel delivery line as caused by failure of fuel to said fuel pump operates said means for rendering said vent inoperative and subsequent rise of fuel pressure again operates said means oppositely and thereby renders the vent' operative.

4; A fuel system for a high pressure carburetor comprising a fuel pump, a fuel delivery line from said fuel pump to a pressure opened jet of the carburetor, a chamber in said fuel delivery line adapted to initially receive a reserve supply of fuel from said fuel pump before the fuel is dellvered to the caurburetor, a valve responsive to a drop in fuel pressure to a predetermined degree below normal operating pressure to open and thereby permit introduction of fluid pressure to said reserve chamber, such fluid pressure building up to displace the fuel from said re serve chamber, said valve responding to subseo livery line adapted to quent build-up of fuel pressure to normal and thereby assuming its initial position opened another way and thereby permitting escape of the fluid pressure from the reserve chamber, and signal means responsive to the fuel pressure and operable at a pressure slightly exceeding said predetermined degree below normal operating pressure.

5. A fuel system for a carburetor or the like comprising a fuel pump, a fuel delivery line from the discharge side of said fuel pump to a normaily closed and pressure opened iet ofthe carburetor, a reserve fuel chamber in said fuel deinitially receive a reserve supply of fuel from said fuel Dump before the fuel is delivered to the carburetor, and a valve responsive to a drop in fuel pressure to a predetermined degree below normal operating pressure and above the pressure required to open said jet, to open one way and thereby build up fluid pressure to said reserve fuel chamber to displace the fuel therefrom, said valve, upon responding to subsequent buildfup of fue] pressure to normal assuming its initial position opening the other way and therebyrpermitting escape of the iiuid pressure from the reserve chamber.A

6. A fuel system for a carburetor or the like comprising a fuel pump, a fuel delivery line from the discharge side of said fuel pump to a nor..

mally closed and pressure opened jet of the carburetor, a reserve fuel chamber in said fuel delivery line having a first compartment adapted to initially receive a reserve supply of fue] from said fuel pump before the fuel is delivered to the carburetor, said reserve fuel chamber having a second compartment and a diaphragm separating said compartments, and means responsive to a drop in fuel pressure below normal operating pressure and above the pressure required to open said jet to introduce fluid pressure to said second compartment to displace the fuel from said first compartment to said carburetor under a pressure sufficient to operate it, said means being revertible to initial position upon subsequent buildup of fuel pressure to normal and permitting escape of the fluid pressure from said second compartment.

7. In a fuel system for a high pressure carburetor, a fuel pump, a fuel delivery line from the discharge side of said fuel pump to a normally closed and fuel pressure opened jet of said carburetor, a reserve fuel chamber in said fuel delivery line, an air pressure control valve connected with said chamber and havinga pressure responsive actuating elementrresponsive to the pressure of fuel. said fuel pump, upon receiving air, effecting displacement of fuel from said chamber at a pressure sufficient for operation of said carburetor jet by pumping air thereto, and means for eliminating air from said fuel delivery line when said fuel pump subsequently receives fuel from a new source.

8. In a f-uel system of the character described, a fuel pump, a fuel delivery line from the discharge side of said fuel pump to a normally closed and fuel pressure opened iet of a. carburetor, an air eliminator in said fuel delivery line, said air eliminator including a float operated air eliminating vent and means for closing said vent, said means comprising an air control valve having an actuating element responsive to the pressure of the fuel from said air eliminatorr said control valve, upon a predetermined drop in pressure in said fuel delivery line, closing said valve and admitting fluid pressure to said air Y `until `a further supply of Vfuel pump and the fuel pressure as a result eliminator to supplement air delivered thereto by said fuel pump as a result of fuel failing at the intake side of said pump.

9. In a fuel system for high pressure carburetors, a fuel pump, the discharge side thereof to the jet of the carburetor, a reserve chamber in said fuel delivery line, said chamber including a vent, a valve connected with said vent and operable to closed position upon predetermined pressure dropl in the fuel delivered from said reserve chamber, and means operable by closure of said vent to supply air from said fuel pump to saidv reserve chamber to displace. the sumcient operating pressure to said carburetor fuel is furnished to said thereof rises to normal 10. In a fuel system in said fuel delivery line.

for high pressure carburetors, a fuel pump, a fuel delivery line from the discharge thereof to the jet of the carburetor, said jet requiring predetermined fuel pressure introduction to effect opening thereof, an air eliminator in said fuel delivery line and including a float operated vent, means for rendering said vent inoperative upon said fuel pump receiving air, said means comprising an air control valve series-connected Withsaid vent, and pressure responsive means for opening said air control valve, said pressure responsive'means being responsive to fuel pressure in said fuel delivery line whereby predetermined drop in the fuelV pressure therein will close said valve, said valve being `opened by said pressure responsive means as it responds to a further decrease of fuel pressure to another predetermined degree as a result of excessive air delivery to said air eliminator and being reclosed by said pressure responsive means vresponding to fuel pressure rise caused by fuel delivery to the carburetor when such rise of fuel pressure is to a degree intermediate said another predetermined degree and said first mentioned predetermined degree.

11. A fuel system for high pressure carburetors comprising a plurality of fuel tanks, a

fuel pump, a selector valve between said tanks and said pump and connecting one of the tanks with the pump, a fuel delivery line from the discharge side of said fuel pump to the jet of said carburetor, said jet requiring predetermined fuel pressure introduction to effect opening of said jet, an air eliminator in said fuel delivery line and including a float operated vent, means for rendering said vent inoperative upon said fuel pump receiving air, said means comprising anV air pressure control valve in series with said vent, and means for operating said valve, said last means being responsive to fuel pressure and connected with said valve to open it upon the fuel rising to normal operating pressure, and to close it upon predetermined drop in the fuel pressure, and, upon further decrease of fuel pressure, again opening it for kpermitting elimination of air from said eliminator when the pressure'of the fuel to the carburetor is too low to be discharged from the jet thereof. Y

12. A fuel system rof the character disclosed comprising a plurality of fuel tanks, a fuel pump, a selector valve between said tanks and said pump and connecting one of the tanks with the pump, a fuel delivery line from the discharge side of said fuel pump to the iet of a. carburetor,

troduction to in a fuel'delivery line from l contents thereof under operated vent, means for closing the line from said vent upon said fuel pump receiving air, said means comprising an air pressure control valve in series with said vent, a solenoid for operating said valve, and a pressure responsive switch for controlling said solenoid, said switch being responsive to fuel pressure and, upon predetermined drop thereof, closing to thereby energize the solenoid of said valve.

13. In a fuel system of the character disclosed, a fuel pump, a fuel delivery line from the discharge thereof to the jet of a carburetor which requires. predetermined fuel pressure introduction to effect opening of said jet, an air eliminator in said fuel delivery line and including a float operated Vent, a valve series-connected with said vent, and means for opening said valve, said means being responsive to fuel pressure Vin* said fuel delivery line and, upon predetermined drop in the fuel pressure therein, closing said valve, said valve being opened by said means as a result of excessive air delivery to said air eliminator by determined degree less than the degree of pres' sure required to open said jet, said valve being reclosed by said means upon subsequent fuel delivery to the carburetor effecting rise of fuel pressure to a degree intermediatesaid another predetermined degree and said rst mentioned predetermined degree and being reopened by said means upon the fuel attaining normal operating pressure. 1

14.-In a fuel system for a high pressure carburetor, a fuel pump, a fuel delivery line from the discharge side of said fuel pump to a normally closed and fuel pressure opened Jet of said carburetor and an air eliminator in said fueldelivery line,Y said air eliminator including a float operated air eliminating vent, an air pressure control valve connected therewith and having an actuating element responsive to the pressure of fuel from said vair eliminator to close said valve upon predetermined drop in pressure in said air eliminator as caused by said fuel pump receiving air, subsequent rise of fuel pressure actingY on said fuel pressure responsive actuated element to cause it to again open said valve, said valve including a signal device operable by the valve assuming its position in response to said fuel pressure responsive actuated element responding to y assenso such predetermined drop in pressure in said fuel line, subsequent rise in pressure in said fuel line as a result of said fuel pump receiving fuel from a new source positioning said actuating element for opening said valve and for rendering said signal device immediately inoperative.

15. In a fuel system for a high pressure carburetor, a fuel pump, a fuel delivery line from the discharge side of said fuel pump to a normally closed and fuel pressure opened jet of said carburetor, an air eliminator in said fuel delivery line, said air eliminator including a float operated air eliminating vent, an air pressure control valve having a pressure responsive actuating element responsive to fuel from said air eliminator, and, upon predetermined drop in pressure in said fuel line as caused by said fuel pump receiving air, opening said valve, said air pressure control valve having connection with an auxiliary source of fluid pressure supply operable to supplement air pumped to said air eliminator by said fuel pump and thereby aid in maintaining sufficient pressure on the fuel in said air eliminator to feed reserve fuel in the eliminator to said carburetorand retain the jet thereof open.

16. In a vfuel system, a fuel pump, a fuel delivery line from the discharge thereof to a car- -buretor whichrequires predetermined fuel pressure for operation, an air eliminator in said fuel delivery line and including anair eliminating vent, means for rendering said vent inoperative upon said fuel pump receiving air, said means being responsive to predetermined drop of fuel pressure in said fuel delivery line, said vent being rendered again operative by further decrease of fuel pressure as a result of excessive air delivery to saidair eliminator Ato another predetermined degree less than the degreeof pressure required to operate said carburetor, said means responsive to fuel pressure including a signal device operable upon such predetermined drop in pressure in said fuel line, a subsequent rise in pressure in said fuel line as a result of fuel being received from a new source by said fuel pump rendering saidsignal device immediately inoperative.

17. In a fuel systemv for carburetors, a fuel pump, a fuel delivery line therefrom to a 'carburetor which requires predetermined fuel pressure introduction to effect operation thereof, an air eliminator in said fuel delivery line and including a float operated vent, means for rendering said vent inoperative upon said fuel pump receiving air, said means comprising a valve series-connected with said vent, pressure responsive means for opening said valve, said pressure'responsive the fuel pressure in said fuel delivery line to close ,said valve, said valve being opened by said'pressure responsive means respond-ing to further decrease of fuel pressure to another predetermined degree less than the degree of pressure required to open said jet,y said air pressure control valve 'including a signal device operable upon such predetermined drop in pressure in said fuel line affecting said pressure responsive means, a subsequent rise in pressure in said fuel line as a result of fuel being'received from a new source by said fuel pump, affecting said` pressure' responsive means and thereby again rendering said device immediately inoperative and opening said valve to permit said vent to function in its normal air eliminating capacity.

. 18. In a fuel system for high pressure carburetors, a fuel pump for delivering fuel to the jet of the carburetor, Asaid jetrequiring a predetermined fuel pressure to eect its opening, an air eliminator in the fuel delivery line and including a float operated vent, means for rendering said vent inoperative upon said fuel pump receiving air, said means comprising a valve series-cone nected with said vent, means responsive to fuel pressure for opening said valve with predetermined drop in the fuel pressure effecting closure of said valve, said valve being opened by further decrease of fuel pressure to another predetermined degree less than the degree of pressure required to open said jet and being reclosed upon fuel delivery to the carburetor effecting a subsequent rise of fuel pressure, said air pressure control valve having connection with an auxiliary source of fluid pressure and operable to admit supplemental air in addition to air pumped to said air eliminator by said fuel pump and thereby aid in maintaining sufficient pressure on the fuel in said air eliminator to feed the lreserve fuel therefrom to said carburetor and retain the jet thereof open. 1 A

19. In a fuel system for high pressure carburetors, a fuel pump for delivering fuel to the jet of the carburetor, said jet requiringa predetermined fuel pressure toei'fect its opening, an air eliminator in the fuel delivery linevand including a float operated vent,` means for rendering said ventl inoperative upon said fuel pump receiving air, said means comprising a valve series-connectedvwith said vent, means responsive to fuel pressure for opening said valve with predetermined drop in the fuel pressure effecting closure of said'valvesaid valve beingopened by further decrease of fuel pressure to another predetermined-'degree less than thedegree of pressure required to open saidjet' and being reclosed upon fuel delivery to the carburetor effecting a subsequent rise of fuel pressure. said air pressure control valve having connection with an auxiliary source of 'fluid pressure and operable to admit supplemental air in addition to air pumped to said air eliminator by said fuel pump and'thereby aid in maintaining suillcient pressure on the fuel in said air eliminator to feed the reserve fuel therefrom to said: carburetor and retain the jet thereof open, said air pressure control valve inciuding a signal device operable upon such predetermined drop in pressure in said fuel line, a subsequent rise` in pressure in said fuel line as a result of: fuel: being' received from a new source by said fuel,` pump again 'rendering said signal device immediately inoperative and reopening saidsvalve'.

20. Inalfuelsystemof the character disclosed, afuelrpump, afuel. delivery line from the discharge side` of saidlfuelpump to a normally closed and fuelpressure opened jet of a carburetor or they" like, an aireliminator in said fuelrdelivery line, said air` eliminatorv4 including a float operated' air eliminatingy vent to atmosphere and means for rendering said vent inoperative and Vfor introducing fluid' pressure into said air eliminator; to displace the fuel therefrom at apressure suilioient to operate 'said carburetor in the event of fuel failing at the intake side of said fuel pump, said means comprising anI air, control valve having a pressure responsive actuating element' responsive tothe pressure of the fuel in said fuel delivery line, said-pressure responsive actuating element, upon responding to 'a drop in pressure in said fuel delivery line to a degree between normal and that pressure required to operate said carburetor, closing s aid valve to atmosphere and opening it from ascurce` of fluid pressure to said air eliminator.

21. A fuel system for high pressure carburetors comprising a fuel tank, a fuel pump, a fuel delivery line connecting the tank with a carburetor having a jet requiring predetermined fuel pressure introduction to effect opening thereof,-an air eliminator in said ful delivery line andincluding air eliminating vent means, a pressure drop actuated valve, having a first valve and seat for closing said vent means when the pressure in the fuel delivery line drops due to said fuel pump receiving air, said pressure drop actuated valve having a second valve and seat for opening p said vent means when the pressure of the fuel to Y the carburetor drops further and is too low to be discharged from the jet thereof.

22. In a fuel system for a high pressure carburetor, a fuel pump, a fuel delivery line from the discharge side of said fuel pump to a normally closed and fuel pressure opened jet of said carburetor, an air eliminator in said fuel delivery valve to a position which renders said vent inv operative, and subsequent rise of fuel pressure operates said actuating element and said air pressure control valve to a position which again renders the vent operative, a signal device operable by said air pressure control valve when it renders said vent inoperative, said signal device being immediately inoperable by saidl air pressure control valve when it renders said vent again operative, said air pressure control valve having connection with an auxiliary source of fluid pres- `sure supply and operable to supplement the air pumped to said air eliminator by said fuel pump when said vent isinoperative, and thereby aid in maintaining suicient pressure on the fuel in said air eliminator to feed the reserve fuel therein to said carburetor to retain the jet thereof open.

DAVID SAMIRAN. 

